NEWS
author wenzelm
Sat Oct 20 20:14:16 2001 +0200 (2001-10-20)
changeset 11842 b903d3dabbe2
parent 11817 875ee0c20da2
child 11864 371ce685b0ec
permissions -rw-r--r--
* greatly simplified document preparation setup, including more
graceful interpretation of isatool usedir -i/-d/-D options, and more
instructive isatool mkdir; users should basically be able to get
started with "isatool mkdir Test && isatool make";
* theory dependency graph may now be incorporated into documents;
isatool usedir -g true will produce session_graph.eps/.pdf for use
with \includegraphics of LaTeX;
     1 
     2 Isabelle NEWS -- history user-relevant changes
     3 ==============================================
     4 
     5 New in Isabelle2001 (?? 2001)
     6 -----------------------------
     7 
     8 *** Document preparation ***
     9 
    10 * greatly simplified document preparation setup, including more
    11 graceful interpretation of isatool usedir -i/-d/-D options, and more
    12 instructive isatool mkdir; users should basically be able to get
    13 started with "isatool mkdir Test && isatool make";
    14 
    15 * theory dependency graph may now be incorporated into documents;
    16 isatool usedir -g true will produce session_graph.eps/.pdf for use
    17 with \includegraphics of LaTeX;
    18 
    19 * support bold style (for single symbols only), input syntax is like
    20 this: "\<^bold>\<alpha>" or "\<^bold>A";
    21 
    22 * \<bullet> is now output as bold \cdot by default, which looks much
    23 better in printed text;
    24 
    25 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
    26 note that these symbols are currently unavailable in Proof General /
    27 X-Symbol;
    28 
    29 
    30 *** Isar ***
    31 
    32 * improved proof by cases and induction:
    33   - 'case' command admits impromptu naming of parameters (such as
    34     "case (Suc n)");
    35   - 'induct' method divinates rule instantiation from the inductive
    36     claim; no longer requires excessive ?P bindings for proper
    37     instantiation of cases;
    38   - 'induct' method properly enumerates all possibilities of set/type
    39     rules; as a consequence facts may be also passed through *type*
    40     rules without further ado;
    41   - removed obsolete "(simplified)" and "(stripped)" options of methods;
    42   - added 'print_induct_rules' (covered by help item in Proof General > 3.3);
    43   - moved induct/cases attributes to Pure, methods to Provers;
    44   - generic method setup instantiated for FOL and HOL;
    45 
    46 * Pure: renamed "antecedent" case to "rule_context";
    47 
    48 * Pure: added 'corollary' command;
    49 
    50 * Pure: fixed 'token_translation' command;
    51 
    52 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
    53 
    54 * HOL: 'recdef' now fails on unfinished automated proofs, use
    55 "(permissive)" option to recover old behavior;
    56 
    57 * HOL: 'inductive' now longer features separate (collective)
    58 attributes for 'intros';
    59 
    60 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
    61 
    62 
    63 *** HOL ***
    64 
    65 * HOL: moved over to sane numeral syntax; the new policy is as
    66 follows:
    67 
    68   - 0 and 1 are polymorphic constants, which are defined on any
    69   numeric type (nat, int, real etc.);
    70 
    71   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
    72   binary representation internally;
    73 
    74   - type nat has special constructor Suc, and generally prefers Suc 0
    75   over 1::nat and Suc (Suc 0) over 2::nat;
    76 
    77 This change may cause significant INCOMPATIBILITIES; here are some
    78 hints on converting existing sources:
    79 
    80   - due to the new "num" token, "-0" and "-1" etc. are now atomic
    81   entities, so expressions involving "-" (unary or binary minus) need
    82   to be spaced properly;
    83 
    84   - existing occurrences of "1" may need to be constraint "1::nat" or
    85   even replaced by Suc 0; similar for old "2";
    86 
    87   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
    88 
    89   - remove all special provisions on numerals in proofs;
    90 
    91 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
    92 (beware of argument permutation!);
    93 
    94 * HOL: linorder_less_split superseded by linorder_cases;
    95 
    96 * HOL: added "The" definite description operator; move Hilbert's "Eps"
    97 to peripheral theory "Hilbert_Choice";
    98 
    99 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   100 in this (rare) case use:
   101 
   102   delSWrapper "split_all_tac"
   103   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   104 
   105 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   106 MAY FAIL;
   107 
   108 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   109 Isabelle's type classes, ^ on functions and relations has too general
   110 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   111 necessary to attach explicit type constraints;
   112 
   113 * HOL: syntax translations now work properly with numerals and records
   114 expressions;
   115 
   116 * HOL/GroupTheory: group theory examples including Sylow's theorem, by
   117 Florian Kammüller;
   118 
   119 * HOL: eliminated global items
   120 
   121   const "()" -> "Product_Type.Unity"
   122   type "unit" -> "Product_Type.unit"
   123 
   124 
   125 *** ZF ***
   126 
   127 * ZF: the integer library now covers quotients and remainders, with
   128 many laws relating division to addition, multiplication, etc.;
   129 
   130 
   131 *** General ***
   132 
   133 * kernel: meta-level proof terms (by Stefan Berghofer), see also ref
   134 manual;
   135 
   136 * classical reasoner: renamed addaltern to addafter, addSaltern to
   137 addSafter;
   138 
   139 * syntax: new token syntax "num" for plain numerals (without "#" of
   140 "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now separate
   141 tokens, so expressions involving minus need to be spaced properly;
   142 
   143 * syntax: support non-oriented infixes;
   144 
   145 * syntax: print modes "type_brackets" and "no_type_brackets" control
   146 output of nested => (types); the default behavior is "type_brackets";
   147 
   148 * syntax: builtin parse translation for "_constify" turns valued
   149 tokens into AST constants;
   150 
   151 * system: support Poly/ML 4.1.1 (now able to manage large heaps);
   152 
   153 * system: Proof General keywords specification is now part of the
   154 Isabelle distribution (see etc/isar-keywords.el);
   155 
   156 * system: smart selection of Isabelle process versus Isabelle
   157 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   158 run both "isabelle" and "Isabelle" even if file names are badly
   159 damaged (executable inspects the case of the first letter of its own
   160 name); added separate "isabelle-process" and "isabelle-interface";
   161 
   162 
   163 
   164 New in Isabelle99-2 (February 2001)
   165 -----------------------------------
   166 
   167 *** Overview of INCOMPATIBILITIES ***
   168 
   169 * HOL: please note that theories in the Library and elsewhere often use the
   170 new-style (Isar) format; to refer to their theorems in an ML script you must
   171 bind them to ML identifers by e.g.	val thm_name = thm "thm_name";
   172 
   173 * HOL: inductive package no longer splits induction rule aggressively,
   174 but only as far as specified by the introductions given; the old
   175 format may be recovered via ML function complete_split_rule or attribute
   176 'split_rule (complete)';
   177 
   178 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   179 gfp_Tarski to gfp_unfold;
   180 
   181 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   182 
   183 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   184 relation); infix "^^" has been renamed "``"; infix "``" has been
   185 renamed "`"; "univalent" has been renamed "single_valued";
   186 
   187 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   188 operation;
   189 
   190 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   191 
   192 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   193 
   194 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   195 consequence, it is no longer monotonic wrt. the local goal context
   196 (which is now passed through the inductive cases);
   197 
   198 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   199 \<gg> to \<ggreater>;
   200 
   201 
   202 *** Document preparation ***
   203 
   204 * \isabellestyle{NAME} selects version of Isabelle output (currently
   205 available: are "it" for near math-mode best-style output, "sl" for
   206 slanted text style, and "tt" for plain type-writer; if no
   207 \isabellestyle command is given, output is according to slanted
   208 type-writer);
   209 
   210 * support sub/super scripts (for single symbols only), input syntax is
   211 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   212 
   213 * some more standard symbols; see Appendix A of the system manual for
   214 the complete list of symbols defined in isabellesym.sty;
   215 
   216 * improved isabelle style files; more abstract symbol implementation
   217 (should now use \isamath{...} and \isatext{...} in custom symbol
   218 definitions);
   219 
   220 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   221 state; Note that presentation of goal states does not conform to
   222 actual human-readable proof documents.  Please do not include goal
   223 states into document output unless you really know what you are doing!
   224 
   225 * proper indentation of antiquoted output with proportional LaTeX
   226 fonts;
   227 
   228 * no_document ML operator temporarily disables LaTeX document
   229 generation;
   230 
   231 * isatool unsymbolize tunes sources for plain ASCII communication;
   232 
   233 
   234 *** Isar ***
   235 
   236 * Pure: Isar now suffers initial goal statements to contain unbound
   237 schematic variables (this does not conform to actual readable proof
   238 documents, due to unpredictable outcome and non-compositional proof
   239 checking); users who know what they are doing may use schematic goals
   240 for Prolog-style synthesis of proven results;
   241 
   242 * Pure: assumption method (an implicit finishing) now handles actual
   243 rules as well;
   244 
   245 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   246 initial goal, declare "that" only as Pure intro (only for single
   247 steps); the "that" rule assumption may now be involved in implicit
   248 finishing, thus ".." becomes a feasible for trivial obtains;
   249 
   250 * Pure: default proof step now includes 'intro_classes'; thus trivial
   251 instance proofs may be performed by "..";
   252 
   253 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   254 statements as well;
   255 
   256 * Pure: more robust selection of calculational rules;
   257 
   258 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   259 rule (as well as the assumption rule);
   260 
   261 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   262 lemmas, using the graph browser tool;
   263 
   264 * Pure: predict failure of "show" in interactive mode;
   265 
   266 * Pure: 'thms_containing' now takes actual terms as arguments;
   267 
   268 * HOL: improved method 'induct' --- now handles non-atomic goals
   269 (potential INCOMPATIBILITY); tuned error handling;
   270 
   271 * HOL: cases and induct rules now provide explicit hints about the
   272 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   273 any remaining facts are inserted into the goal verbatim;
   274 
   275 * HOL: local contexts (aka cases) may now contain term bindings as
   276 well; the 'cases' and 'induct' methods new provide a ?case binding for
   277 the result to be shown in each case;
   278 
   279 * HOL: added 'recdef_tc' command;
   280 
   281 * isatool convert assists in eliminating legacy ML scripts;
   282 
   283 
   284 *** HOL ***
   285 
   286 * HOL/Library: a collection of generic theories to be used together
   287 with main HOL; the theory loader path already includes this directory
   288 by default; the following existing theories have been moved here:
   289 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   290 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   291 
   292 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   293 modelling and verification task performed in Isabelle/HOL +
   294 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   295 
   296 * HOL/Algebra: special summation operator SUM no longer exists, it has
   297 been replaced by setsum; infix 'assoc' now has priority 50 (like
   298 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   299 'domain', this makes the theory consistent with mathematical
   300 literature;
   301 
   302 * HOL basics: added overloaded operations "inverse" and "divide"
   303 (infix "/"), syntax for generic "abs" operation, generic summation
   304 operator \<Sum>;
   305 
   306 * HOL/typedef: simplified package, provide more useful rules (see also
   307 HOL/subset.thy);
   308 
   309 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   310 now expressed as a proper nested rule (old-style tactic scripts may
   311 require atomize_strip_tac to cope with non-atomic premises);
   312 
   313 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   314 to "split_conv" (old name still available for compatibility);
   315 
   316 * HOL: improved concrete syntax for strings (e.g. allows translation
   317 rules with string literals);
   318 
   319 * HOL-Hyperreal: a new target, extending HOL-Real with the hyperreals
   320 and Fleuriot's mechanization of analysis;
   321 
   322 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   323 
   324 
   325 *** CTT ***
   326 
   327 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   328 "lam" is displayed as TWO lambda-symbols
   329 
   330 * CTT: theory Main now available, containing everything (that is, Bool
   331 and Arith);
   332 
   333 
   334 *** General ***
   335 
   336 * Pure: the Simplifier has been implemented properly as a derived rule
   337 outside of the actual kernel (at last!); the overall performance
   338 penalty in practical applications is about 50%, while reliability of
   339 the Isabelle inference kernel has been greatly improved;
   340 
   341 * print modes "brackets" and "no_brackets" control output of nested =>
   342 (types) and ==> (props); the default behaviour is "brackets";
   343 
   344 * Provers: fast_tac (and friends) now handle actual object-logic rules
   345 as assumptions as well;
   346 
   347 * system: support Poly/ML 4.0;
   348 
   349 * system: isatool install handles KDE version 1 or 2;
   350 
   351 
   352 
   353 New in Isabelle99-1 (October 2000)
   354 ----------------------------------
   355 
   356 *** Overview of INCOMPATIBILITIES ***
   357 
   358 * HOL: simplification of natural numbers is much changed; to partly
   359 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   360 issue the following ML commands:
   361 
   362   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   363   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   364 
   365 * HOL: simplification no longer dives into case-expressions; this is
   366 controlled by "t.weak_case_cong" for each datatype t;
   367 
   368 * HOL: nat_less_induct renamed to less_induct;
   369 
   370 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   371 fixsome to patch .thy and .ML sources automatically;
   372 
   373   select_equality  -> some_equality
   374   select_eq_Ex     -> some_eq_ex
   375   selectI2EX       -> someI2_ex
   376   selectI2         -> someI2
   377   selectI          -> someI
   378   select1_equality -> some1_equality
   379   Eps_sym_eq       -> some_sym_eq_trivial
   380   Eps_eq           -> some_eq_trivial
   381 
   382 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   383 
   384 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   385 instead);
   386 
   387 * HOL: the recursion equations generated by 'recdef' are now called
   388 f.simps instead of f.rules;
   389 
   390 * HOL: qed_spec_mp now also handles bounded ALL as well;
   391 
   392 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   393 sometimes be needed;
   394 
   395 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   396 
   397 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   398 
   399 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   400 product is now "<*>" instead of "Times"; the lexicographic product is
   401 now "<*lex*>" instead of "**";
   402 
   403 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   404 of main HOL, but was unused); better use HOL's datatype package;
   405 
   406 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   407 the old syntax may be recovered as follows:
   408 
   409   syntax (symbols)
   410     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   411       (infixl "\\<oplus>" 100)
   412 
   413 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   414 
   415 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   416 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   417 internally;
   418 
   419 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   420 changed from A/r to A//r;
   421 
   422 * ZF: new treatment of arithmetic (nat & int) may break some old
   423 proofs;
   424 
   425 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   426 rulify -> rule_format, elimify -> elim_format, ...);
   427 
   428 * Isar/Provers: intro/elim/dest attributes changed; renamed
   429 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   430 should have to change intro!! to intro? only); replaced "delrule" by
   431 "rule del";
   432 
   433 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   434 
   435 * Provers: strengthened force_tac by using new first_best_tac;
   436 
   437 * LaTeX document preparation: several changes of isabelle.sty (see
   438 lib/texinputs);
   439 
   440 
   441 *** Document preparation ***
   442 
   443 * formal comments (text blocks etc.) in new-style theories may now
   444 contain antiquotations of thm/prop/term/typ/text to be presented
   445 according to latex print mode; concrete syntax is like this:
   446 @{term[show_types] "f(x) = a + x"};
   447 
   448 * isatool mkdir provides easy setup of Isabelle session directories,
   449 including proper document sources;
   450 
   451 * generated LaTeX sources are now deleted after successful run
   452 (isatool document -c); may retain a copy somewhere else via -D option
   453 of isatool usedir;
   454 
   455 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   456 style files, achieving self-contained LaTeX sources and simplifying
   457 LaTeX debugging;
   458 
   459 * old-style theories now produce (crude) LaTeX output as well;
   460 
   461 * browser info session directories are now self-contained (may be put
   462 on WWW server seperately); improved graphs of nested sessions; removed
   463 graph for 'all sessions';
   464 
   465 * several improvements in isabelle style files; \isabellestyle{it}
   466 produces fake math mode output; \isamarkupheader is now \section by
   467 default; see lib/texinputs/isabelle.sty etc.;
   468 
   469 
   470 *** Isar ***
   471 
   472 * Isar/Pure: local results and corresponding term bindings are now
   473 subject to Hindley-Milner polymorphism (similar to ML); this
   474 accommodates incremental type-inference very nicely;
   475 
   476 * Isar/Pure: new derived language element 'obtain' supports
   477 generalized existence reasoning;
   478 
   479 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
   480 support accumulation of results, without applying any rules yet;
   481 useful to collect intermediate results without explicit name
   482 references, and for use with transitivity rules with more than 2
   483 premises;
   484 
   485 * Isar/Pure: scalable support for case-analysis type proofs: new
   486 'case' language element refers to local contexts symbolically, as
   487 produced by certain proof methods; internally, case names are attached
   488 to theorems as "tags";
   489 
   490 * Isar/Pure: theory command 'hide' removes declarations from
   491 class/type/const name spaces;
   492 
   493 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
   494 indicate potential overloading;
   495 
   496 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
   497 
   498 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
   499 "{a,b,c}" instead of {a,b,c};
   500 
   501 * Isar/Pure now provides its own version of intro/elim/dest
   502 attributes; useful for building new logics, but beware of confusion
   503 with the version in Provers/classical;
   504 
   505 * Isar/Pure: the local context of (non-atomic) goals is provided via
   506 case name 'antecedent';
   507 
   508 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
   509 to the current context is now done automatically);
   510 
   511 * Isar/Pure: theory command 'method_setup' provides a simple interface
   512 for definining proof methods in ML;
   513 
   514 * Isar/Provers: intro/elim/dest attributes changed; renamed
   515 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
   516 most cases, one should have to change intro!! to intro? only);
   517 replaced "delrule" by "rule del";
   518 
   519 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
   520 'symmetric' attribute (the latter supercedes [RS sym]);
   521 
   522 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
   523 method modifier); 'simp' method: 'only:' modifier removes loopers as
   524 well (including splits);
   525 
   526 * Isar/Provers: Simplifier and Classical methods now support all kind
   527 of modifiers used in the past, including 'cong', 'iff', etc.
   528 
   529 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
   530 of Simplifier and Classical reasoner);
   531 
   532 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
   533 now support named cases; major packages (inductive, datatype, primrec,
   534 recdef) support case names and properly name parameters;
   535 
   536 * Isar/HOL: new transitivity rules for substitution in inequalities --
   537 monotonicity conditions are extracted to be proven at end of
   538 calculations;
   539 
   540 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
   541 method anyway;
   542 
   543 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
   544 split_if split_if_asm; datatype package provides theorems foo.splits =
   545 foo.split foo.split_asm for each datatype;
   546 
   547 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
   548 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
   549 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
   550 use "(cases (simplified))" method in proper proof texts);
   551 
   552 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
   553 
   554 * Isar: names of theorems etc. may be natural numbers as well;
   555 
   556 * Isar: 'pr' command: optional arguments for goals_limit and
   557 ProofContext.prems_limit; no longer prints theory contexts, but only
   558 proof states;
   559 
   560 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
   561 additional print modes to be specified; e.g. "pr(latex)" will print
   562 proof state according to the Isabelle LaTeX style;
   563 
   564 * Isar: improved support for emulating tactic scripts, including proof
   565 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
   566 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
   567 (for HOL datatypes);
   568 
   569 * Isar: simplified (more robust) goal selection of proof methods: 1st
   570 goal, all goals, or explicit goal specifier (tactic emulation); thus
   571 'proof method scripts' have to be in depth-first order;
   572 
   573 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
   574 
   575 * Isar: removed 'help' command, which hasn't been too helpful anyway;
   576 should instead use individual commands for printing items
   577 (print_commands, print_methods etc.);
   578 
   579 * Isar: added 'nothing' --- the empty list of theorems;
   580 
   581 
   582 *** HOL ***
   583 
   584 * HOL/MicroJava: formalization of a fragment of Java, together with a
   585 corresponding virtual machine and a specification of its bytecode
   586 verifier and a lightweight bytecode verifier, including proofs of
   587 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
   588 Cornelia Pusch (see also the homepage of project Bali at
   589 http://isabelle.in.tum.de/Bali/);
   590 
   591 * HOL/Algebra: new theory of rings and univariate polynomials, by
   592 Clemens Ballarin;
   593 
   594 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
   595 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
   596 Rasmussen;
   597 
   598 * HOL/Lattice: fundamental concepts of lattice theory and order
   599 structures, including duals, properties of bounds versus algebraic
   600 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
   601 Theorem for complete lattices etc.; may also serve as a demonstration
   602 for abstract algebraic reasoning using axiomatic type classes, and
   603 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
   604 
   605 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
   606 von Oheimb;
   607 
   608 * HOL/IMPP: extension of IMP with local variables and mutually
   609 recursive procedures, by David von Oheimb;
   610 
   611 * HOL/Lambda: converted into new-style theory and document;
   612 
   613 * HOL/ex/Multiquote: example of multiple nested quotations and
   614 anti-quotations -- basically a generalized version of de-Bruijn
   615 representation; very useful in avoiding lifting of operations;
   616 
   617 * HOL/record: added general record equality rule to simpset; fixed
   618 select-update simplification procedure to handle extended records as
   619 well; admit "r" as field name;
   620 
   621 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
   622 other numeric types and also as the identity of groups, rings, etc.;
   623 
   624 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
   625 Types nat and int belong to this axclass;
   626 
   627 * HOL: greatly improved simplification involving numerals of type nat, int, real:
   628    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
   629    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
   630   two terms #m*u and #n*u are replaced by #(m+n)*u
   631     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
   632   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
   633     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
   634 
   635 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
   636 powerful prover for predicate logic but knows nothing of clasets; see
   637 ex/mesontest.ML and ex/mesontest2.ML for example applications;
   638 
   639 * HOL: new version of "case_tac" subsumes both boolean case split and
   640 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
   641 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
   642 
   643 * HOL: simplification no longer dives into case-expressions: only the
   644 selector expression is simplified, but not the remaining arms; to
   645 enable full simplification of case-expressions for datatype t, you may
   646 remove t.weak_case_cong from the simpset, either globally (Delcongs
   647 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
   648 
   649 * HOL/recdef: the recursion equations generated by 'recdef' for
   650 function 'f' are now called f.simps instead of f.rules; if all
   651 termination conditions are proved automatically, these simplification
   652 rules are added to the simpset, as in primrec; rules may be named
   653 individually as well, resulting in a separate list of theorems for
   654 each equation;
   655 
   656 * HOL/While is a new theory that provides a while-combinator. It
   657 permits the definition of tail-recursive functions without the
   658 provision of a termination measure. The latter is necessary once the
   659 invariant proof rule for while is applied.
   660 
   661 * HOL: new (overloaded) notation for the set of elements below/above
   662 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
   663 
   664 * HOL: theorems impI, allI, ballI bound as "strip";
   665 
   666 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
   667 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
   668 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
   669 
   670 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   671 
   672 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
   673 main HOL, but was unused);
   674 
   675 * HOL: fewer consts declared as global (e.g. have to refer to
   676 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
   677 
   678 * HOL: tuned AST representation of nested pairs, avoiding bogus output
   679 in case of overlap with user translations (e.g. judgements over
   680 tuples); (note that the underlying logical represenation is still
   681 bogus);
   682 
   683 
   684 *** ZF ***
   685 
   686 * ZF: simplification automatically cancels common terms in arithmetic
   687 expressions over nat and int;
   688 
   689 * ZF: new treatment of nat to minimize type-checking: all operators
   690 coerce their operands to a natural number using the function natify,
   691 making the algebraic laws unconditional;
   692 
   693 * ZF: as above, for int: operators coerce their operands to an integer
   694 using the function intify;
   695 
   696 * ZF: the integer library now contains many of the usual laws for the
   697 orderings, including $<=, and monotonicity laws for $+ and $*;
   698 
   699 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
   700 simplification;
   701 
   702 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
   703 to the simplifier and classical reasoner simultaneously;
   704 
   705 
   706 *** General ***
   707 
   708 * Provers: blast_tac now handles actual object-logic rules as
   709 assumptions; note that auto_tac uses blast_tac internally as well;
   710 
   711 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
   712 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
   713 
   714 * Provers: delrules now handles destruct rules as well (no longer need
   715 explicit make_elim);
   716 
   717 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
   718   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   719 use instead the strong form,
   720   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   721 in HOL, FOL and ZF the function cla_make_elim will create such rules
   722 from destruct-rules;
   723 
   724 * Provers: Simplifier.easy_setup provides a fast path to basic
   725 Simplifier setup for new object-logics;
   726 
   727 * Pure: AST translation rules no longer require constant head on LHS;
   728 
   729 * Pure: improved name spaces: ambiguous output is qualified; support
   730 for hiding of names;
   731 
   732 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
   733 XSYMBOL_HOME; no longer need to do manual configuration in most
   734 situations;
   735 
   736 * system: compression of ML heaps images may now be controlled via -c
   737 option of isabelle and isatool usedir (currently only observed by
   738 Poly/ML);
   739 
   740 * system: isatool installfonts may handle X-Symbol fonts as well (very
   741 useful for remote X11);
   742 
   743 * system: provide TAGS file for Isabelle sources;
   744 
   745 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
   746 order;
   747 
   748 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
   749 timing flag supersedes proof_timing and Toplevel.trace;
   750 
   751 * ML: new combinators |>> and |>>> for incremental transformations
   752 with secondary results (e.g. certain theory extensions):
   753 
   754 * ML: PureThy.add_defs gets additional argument to indicate potential
   755 overloading (usually false);
   756 
   757 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
   758 results;
   759 
   760 
   761 
   762 New in Isabelle99 (October 1999)
   763 --------------------------------
   764 
   765 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   766 
   767 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
   768 are no longer simplified.  (This allows the simplifier to unfold recursive
   769 functional programs.)  To restore the old behaviour, declare
   770 
   771     Delcongs [if_weak_cong];
   772 
   773 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
   774 complement;
   775 
   776 * HOL: the predicate "inj" is now defined by translation to "inj_on";
   777 
   778 * HOL/datatype: mutual_induct_tac no longer exists --
   779   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
   780 
   781 * HOL/typedef: fixed type inference for representing set; type
   782 arguments now have to occur explicitly on the rhs as type constraints;
   783 
   784 * ZF: The con_defs part of an inductive definition may no longer refer
   785 to constants declared in the same theory;
   786 
   787 * HOL, ZF: the function mk_cases, generated by the inductive
   788 definition package, has lost an argument.  To simplify its result, it
   789 uses the default simpset instead of a supplied list of theorems.
   790 
   791 * HOL/List: the constructors of type list are now Nil and Cons;
   792 
   793 * Simplifier: the type of the infix ML functions
   794         setSSolver addSSolver setSolver addSolver
   795 is now  simpset * solver -> simpset  where `solver' is a new abstract type
   796 for packaging solvers. A solver is created via
   797         mk_solver: string -> (thm list -> int -> tactic) -> solver
   798 where the string argument is only a comment.
   799 
   800 
   801 *** Proof tools ***
   802 
   803 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
   804 decision procedure for linear arithmetic. Currently it is used for
   805 types `nat', `int', and `real' in HOL (see below); it can, should and
   806 will be instantiated for other types and logics as well.
   807 
   808 * The simplifier now accepts rewrite rules with flexible heads, eg
   809      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
   810   They are applied like any rule with a non-pattern lhs, i.e. by first-order
   811   matching.
   812 
   813 
   814 *** General ***
   815 
   816 * New Isabelle/Isar subsystem provides an alternative to traditional
   817 tactical theorem proving; together with the ProofGeneral/isar user
   818 interface it offers an interactive environment for developing human
   819 readable proof documents (Isar == Intelligible semi-automated
   820 reasoning); for further information see isatool doc isar-ref,
   821 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
   822 
   823 * improved and simplified presentation of theories: better HTML markup
   824 (including colors), graph views in several sizes; isatool usedir now
   825 provides a proper interface for user theories (via -P option); actual
   826 document preparation based on (PDF)LaTeX is available as well (for
   827 new-style theories only); see isatool doc system for more information;
   828 
   829 * native support for Proof General, both for classic Isabelle and
   830 Isabelle/Isar;
   831 
   832 * ML function thm_deps visualizes dependencies of theorems and lemmas,
   833 using the graph browser tool;
   834 
   835 * Isabelle manuals now also available as PDF;
   836 
   837 * theory loader rewritten from scratch (may not be fully
   838 bug-compatible); old loadpath variable has been replaced by show_path,
   839 add_path, del_path, reset_path functions; new operations such as
   840 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
   841 isatool doc ref);
   842 
   843 * improved isatool install: option -k creates KDE application icon,
   844 option -p DIR installs standalone binaries;
   845 
   846 * added ML_PLATFORM setting (useful for cross-platform installations);
   847 more robust handling of platform specific ML images for SML/NJ;
   848 
   849 * the settings environment is now statically scoped, i.e. it is never
   850 created again in sub-processes invoked from isabelle, isatool, or
   851 Isabelle;
   852 
   853 * path element specification '~~' refers to '$ISABELLE_HOME';
   854 
   855 * in locales, the "assumes" and "defines" parts may be omitted if
   856 empty;
   857 
   858 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
   859 long arrows);
   860 
   861 * new print_mode "HTML";
   862 
   863 * new flag show_tags controls display of tags of theorems (which are
   864 basically just comments that may be attached by some tools);
   865 
   866 * Isamode 2.6 requires patch to accomodate change of Isabelle font
   867 mode and goal output format:
   868 
   869 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
   870 244c244
   871 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
   872 ---
   873 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
   874 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
   875 181c181
   876 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
   877 ---
   878 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
   879 
   880 * function bind_thms stores lists of theorems (cf. bind_thm);
   881 
   882 * new shorthand tactics ftac, eatac, datac, fatac;
   883 
   884 * qed (and friends) now accept "" as result name; in that case the
   885 theorem is not stored, but proper checks and presentation of the
   886 result still apply;
   887 
   888 * theorem database now also indexes constants "Trueprop", "all",
   889 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
   890 
   891 
   892 *** HOL ***
   893 
   894 ** HOL arithmetic **
   895 
   896 * There are now decision procedures for linear arithmetic over nat and
   897 int:
   898 
   899 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
   900 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
   901 are treated as atomic; subformulae not involving type `nat' or `int'
   902 are ignored; quantified subformulae are ignored unless they are
   903 positive universal or negative existential. The tactic has to be
   904 invoked by hand and can be a little bit slow. In particular, the
   905 running time is exponential in the number of occurrences of `min' and
   906 `max', and `-' on `nat'.
   907 
   908 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
   909 (negated) (in)equalities among the premises and the conclusion into
   910 account (i.e. no compound formulae) and does not know about `min' and
   911 `max', and `-' on `nat'. It is fast and is used automatically by the
   912 simplifier.
   913 
   914 NB: At the moment, these decision procedures do not cope with mixed
   915 nat/int formulae where the two parts interact, such as `m < n ==>
   916 int(m) < int(n)'.
   917 
   918 * HOL/Numeral provides a generic theory of numerals (encoded
   919 efficiently as bit strings); setup for types nat/int/real is in place;
   920 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
   921 int, existing theories and proof scripts may require a few additional
   922 type constraints;
   923 
   924 * integer division and remainder can now be performed on constant
   925 arguments;
   926 
   927 * many properties of integer multiplication, division and remainder
   928 are now available;
   929 
   930 * An interface to the Stanford Validity Checker (SVC) is available through the
   931 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
   932 are proved automatically.  SVC must be installed separately, and its results
   933 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
   934 invocation of the underlying oracle).  For SVC see
   935   http://verify.stanford.edu/SVC
   936 
   937 * IsaMakefile: the HOL-Real target now builds an actual image;
   938 
   939 
   940 ** HOL misc **
   941 
   942 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
   943 (in Isabelle/Isar) -- by Gertrud Bauer;
   944 
   945 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
   946 analysis for assembly languages with subtypes;
   947 
   948 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
   949 -- avoids syntactic ambiguities and treats state, transition, and
   950 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
   951 changed syntax and (many) tactics;
   952 
   953 * HOL/inductive: Now also handles more general introduction rules such
   954   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
   955   theorems are now maintained within the theory (maintained via the
   956   "mono" attribute);
   957 
   958 * HOL/datatype: Now also handles arbitrarily branching datatypes
   959   (using function types) such as
   960 
   961   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
   962 
   963 * HOL/record: record_simproc (part of the default simpset) takes care
   964 of selectors applied to updated records; record_split_tac is no longer
   965 part of the default claset; update_defs may now be removed from the
   966 simpset in many cases; COMPATIBILITY: old behavior achieved by
   967 
   968   claset_ref () := claset() addSWrapper record_split_wrapper;
   969   Delsimprocs [record_simproc]
   970 
   971 * HOL/typedef: fixed type inference for representing set; type
   972 arguments now have to occur explicitly on the rhs as type constraints;
   973 
   974 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
   975 names rather than an ML expression;
   976 
   977 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
   978 supplied later.  Program schemes can be defined, such as
   979     "While B C s = (if B s then While B C (C s) else s)"
   980 where the well-founded relation can be chosen after B and C have been given.
   981 
   982 * HOL/List: the constructors of type list are now Nil and Cons;
   983 INCOMPATIBILITY: while [] and infix # syntax is still there, of
   984 course, ML tools referring to List.list.op # etc. have to be adapted;
   985 
   986 * HOL_quantifiers flag superseded by "HOL" print mode, which is
   987 disabled by default; run isabelle with option -m HOL to get back to
   988 the original Gordon/HOL-style output;
   989 
   990 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
   991 ALL x<=y. P, EX x<y. P, EX x<=y. P;
   992 
   993 * HOL basic syntax simplified (more orthogonal): all variants of
   994 All/Ex now support plain / symbolic / HOL notation; plain syntax for
   995 Eps operator is provided as well: "SOME x. P[x]";
   996 
   997 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
   998 
   999 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1000 thus available for user theories;
  1001 
  1002 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1003 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1004 time;
  1005 
  1006 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1007 several times and then mp;
  1008 
  1009 
  1010 *** LK ***
  1011 
  1012 * the notation <<...>> is now available as a notation for sequences of
  1013 formulas;
  1014 
  1015 * the simplifier is now installed
  1016 
  1017 * the axiom system has been generalized (thanks to Soren Heilmann)
  1018 
  1019 * the classical reasoner now has a default rule database
  1020 
  1021 
  1022 *** ZF ***
  1023 
  1024 * new primrec section allows primitive recursive functions to be given
  1025 directly (as in HOL) over datatypes and the natural numbers;
  1026 
  1027 * new tactics induct_tac and exhaust_tac for induction (or case
  1028 analysis) over datatypes and the natural numbers;
  1029 
  1030 * the datatype declaration of type T now defines the recursor T_rec;
  1031 
  1032 * simplification automatically does freeness reasoning for datatype
  1033 constructors;
  1034 
  1035 * automatic type-inference, with AddTCs command to insert new
  1036 type-checking rules;
  1037 
  1038 * datatype introduction rules are now added as Safe Introduction rules
  1039 to the claset;
  1040 
  1041 * the syntax "if P then x else y" is now available in addition to
  1042 if(P,x,y);
  1043 
  1044 
  1045 *** Internal programming interfaces ***
  1046 
  1047 * tuned simplifier trace output; new flag debug_simp;
  1048 
  1049 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1050 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1051 
  1052 * AxClass.axclass_tac lost the theory argument;
  1053 
  1054 * tuned current_goals_markers semantics: begin / end goal avoids
  1055 printing empty lines;
  1056 
  1057 * removed prs and prs_fn hook, which was broken because it did not
  1058 include \n in its semantics, forcing writeln to add one
  1059 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1060 string -> unit if you really want to output text without newline;
  1061 
  1062 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1063 plain output, interface builders may have to enable 'isabelle_font'
  1064 mode to get Isabelle font glyphs as before;
  1065 
  1066 * refined token_translation interface; INCOMPATIBILITY: output length
  1067 now of type real instead of int;
  1068 
  1069 * theory loader actions may be traced via new ThyInfo.add_hook
  1070 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1071 your own database of information attached to *whole* theories -- as
  1072 opposed to intra-theory data slots offered via TheoryDataFun;
  1073 
  1074 * proper handling of dangling sort hypotheses (at last!);
  1075 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1076 extra sort hypotheses that can be witnessed from the type signature;
  1077 the force_strip_shyps flag is gone, any remaining shyps are simply
  1078 left in the theorem (with a warning issued by strip_shyps_warning);
  1079 
  1080 
  1081 
  1082 New in Isabelle98-1 (October 1998)
  1083 ----------------------------------
  1084 
  1085 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1086 
  1087 * several changes of automated proof tools;
  1088 
  1089 * HOL: major changes to the inductive and datatype packages, including
  1090 some minor incompatibilities of theory syntax;
  1091 
  1092 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1093 called `inj_on';
  1094 
  1095 * HOL: removed duplicate thms in Arith:
  1096   less_imp_add_less  should be replaced by  trans_less_add1
  1097   le_imp_add_le      should be replaced by  trans_le_add1
  1098 
  1099 * HOL: unary minus is now overloaded (new type constraints may be
  1100 required);
  1101 
  1102 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1103 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1104 now taken as an integer constant.
  1105 
  1106 * Pure: ML function 'theory_of' renamed to 'theory';
  1107 
  1108 
  1109 *** Proof tools ***
  1110 
  1111 * Simplifier:
  1112   1. Asm_full_simp_tac is now more aggressive.
  1113      1. It will sometimes reorient premises if that increases their power to
  1114         simplify.
  1115      2. It does no longer proceed strictly from left to right but may also
  1116         rotate premises to achieve further simplification.
  1117      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1118      old Asm_full_simp_tac in that it does not rotate premises.
  1119   2. The simplifier now knows a little bit about nat-arithmetic.
  1120 
  1121 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1122 allows for selected deletion of wrappers, by introduction of names for
  1123 wrapper functionals.  This implies that addbefore, addSbefore,
  1124 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1125 and that adding two tactics with the same name overwrites the first
  1126 one (emitting a warning).
  1127   type wrapper = (int -> tactic) -> (int -> tactic)
  1128   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1129   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1130   delWrapper, delSWrapper: claset *  string            -> claset
  1131   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1132 
  1133 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1134 semantics; addbefore now affects only the unsafe part of step_tac
  1135 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1136 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1137 by Force_tac;
  1138 
  1139 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1140 compWrapper; added safe wrapper (and access functions for it);
  1141 
  1142 * HOL/split_all_tac is now much faster and fails if there is nothing
  1143 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1144 and the names of the automatically generated variables have changed.
  1145 split_all_tac has moved within claset() from unsafe wrappers to safe
  1146 wrappers, which means that !!-bound variables are split much more
  1147 aggressively, and safe_tac and clarify_tac now split such variables.
  1148 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1149 Note: the same holds for record_split_tac, which does the job of
  1150 split_all_tac for record fields.
  1151 
  1152 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1153 permanently to the default simpset using Addsplits just like
  1154 Addsimps. They can be removed via Delsplits just like
  1155 Delsimps. Lower-case versions are also available.
  1156 
  1157 * HOL/Simplifier: The rule split_if is now part of the default
  1158 simpset. This means that the simplifier will eliminate all occurrences
  1159 of if-then-else in the conclusion of a goal. To prevent this, you can
  1160 either remove split_if completely from the default simpset by
  1161 `Delsplits [split_if]' or remove it in a specific call of the
  1162 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1163 other case splitting rules to/from the default simpset: every datatype
  1164 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1165 t is the name of the datatype).
  1166 
  1167 * Classical reasoner / Simplifier combination: new force_tac (and
  1168 derivatives Force_tac, force) combines rewriting and classical
  1169 reasoning (and whatever other tools) similarly to auto_tac, but is
  1170 aimed to solve the given subgoal completely.
  1171 
  1172 
  1173 *** General ***
  1174 
  1175 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1176 and `goalw': the theory is no longer needed as an explicit argument -
  1177 the current theory context is used; assumptions are no longer returned
  1178 at the ML-level unless one of them starts with ==> or !!; it is
  1179 recommended to convert to these new commands using isatool fixgoal
  1180 (backup your sources first!);
  1181 
  1182 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1183 the current theory context, and 'theory' to lookup stored theories;
  1184 
  1185 * new theory section 'locale' for declaring constants, assumptions and
  1186 definitions that have local scope;
  1187 
  1188 * new theory section 'nonterminals' for purely syntactic types;
  1189 
  1190 * new theory section 'setup' for generic ML setup functions
  1191 (e.g. package initialization);
  1192 
  1193 * the distribution now includes Isabelle icons: see
  1194 lib/logo/isabelle-{small,tiny}.xpm;
  1195 
  1196 * isatool install - install binaries with absolute references to
  1197 ISABELLE_HOME/bin;
  1198 
  1199 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1200 
  1201 * print mode 'emacs' reserved for Isamode;
  1202 
  1203 * support multiple print (ast) translations per constant name;
  1204 
  1205 * theorems involving oracles are now printed with a suffixed [!];
  1206 
  1207 
  1208 *** HOL ***
  1209 
  1210 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1211 
  1212 * HOL/inductive package reorganized and improved: now supports mutual
  1213 definitions such as
  1214 
  1215   inductive EVEN ODD
  1216     intrs
  1217       null "0 : EVEN"
  1218       oddI "n : EVEN ==> Suc n : ODD"
  1219       evenI "n : ODD ==> Suc n : EVEN"
  1220 
  1221 new theorem list "elims" contains an elimination rule for each of the
  1222 recursive sets; inductive definitions now handle disjunctive premises
  1223 correctly (also ZF);
  1224 
  1225 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1226 "mutual_induct" no longer exists - the induction rule is always
  1227 contained in "induct";
  1228 
  1229 
  1230 * HOL/datatype package re-implemented and greatly improved: now
  1231 supports mutually recursive datatypes such as
  1232 
  1233   datatype
  1234     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1235             | SUM ('a aexp) ('a aexp)
  1236             | DIFF ('a aexp) ('a aexp)
  1237             | NUM 'a
  1238   and
  1239     'a bexp = LESS ('a aexp) ('a aexp)
  1240             | AND ('a bexp) ('a bexp)
  1241             | OR ('a bexp) ('a bexp)
  1242 
  1243 as well as indirectly recursive datatypes such as
  1244 
  1245   datatype
  1246     ('a, 'b) term = Var 'a
  1247                   | App 'b ((('a, 'b) term) list)
  1248 
  1249 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1250 induction on mutually / indirectly recursive datatypes.
  1251 
  1252 Primrec equations are now stored in theory and can be accessed via
  1253 <function_name>.simps.
  1254 
  1255 INCOMPATIBILITIES:
  1256 
  1257   - Theories using datatypes must now have theory Datatype as an
  1258     ancestor.
  1259   - The specific <typename>.induct_tac no longer exists - use the
  1260     generic induct_tac instead.
  1261   - natE has been renamed to nat.exhaust - use exhaust_tac
  1262     instead of res_inst_tac ... natE. Note that the variable
  1263     names in nat.exhaust differ from the names in natE, this
  1264     may cause some "fragile" proofs to fail.
  1265   - The theorems split_<typename>_case and split_<typename>_case_asm
  1266     have been renamed to <typename>.split and <typename>.split_asm.
  1267   - Since default sorts of type variables are now handled correctly,
  1268     some datatype definitions may have to be annotated with explicit
  1269     sort constraints.
  1270   - Primrec definitions no longer require function name and type
  1271     of recursive argument.
  1272 
  1273 Consider using isatool fixdatatype to adapt your theories and proof
  1274 scripts to the new package (backup your sources first!).
  1275 
  1276 
  1277 * HOL/record package: considerably improved implementation; now
  1278 includes concrete syntax for record types, terms, updates; theorems
  1279 for surjective pairing and splitting !!-bound record variables; proof
  1280 support is as follows:
  1281 
  1282   1) standard conversions (selectors or updates applied to record
  1283 constructor terms) are part of the standard simpset;
  1284 
  1285   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1286 made part of standard simpset and claset via addIffs;
  1287 
  1288   3) a tactic for record field splitting (record_split_tac) is part of
  1289 the standard claset (addSWrapper);
  1290 
  1291 To get a better idea about these rules you may retrieve them via
  1292 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1293 the name of your record type.
  1294 
  1295 The split tactic 3) conceptually simplifies by the following rule:
  1296 
  1297   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1298 
  1299 Thus any record variable that is bound by meta-all will automatically
  1300 blow up into some record constructor term, consequently the
  1301 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1302 solve record problems automatically.
  1303 
  1304 
  1305 * reorganized the main HOL image: HOL/Integ and String loaded by
  1306 default; theory Main includes everything;
  1307 
  1308 * automatic simplification of integer sums and comparisons, using cancellation;
  1309 
  1310 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1311 
  1312 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1313 
  1314 * many new identities for unions, intersections, set difference, etc.;
  1315 
  1316 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1317 called split_if, split_split, split_sum_case and split_nat_case (to go
  1318 with add/delsplits);
  1319 
  1320 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1321 (?x::unit) = (); this is made part of the default simpset, which COULD
  1322 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1323 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1324 unit_abs_eta_conv is added in order to counter the effect of
  1325 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1326 %u.f();
  1327 
  1328 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1329 makes more sense);
  1330 
  1331 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1332   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1333   disjointness reasoning but breaking a few old proofs.
  1334 
  1335 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1336 to 'converse' from 'inverse' (for compatibility with ZF and some
  1337 literature);
  1338 
  1339 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1340 the well-founded relation;
  1341 
  1342 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1343     Compl A.  The "Compl" syntax remains available as input syntax for this
  1344     release ONLY.
  1345 
  1346 * HOL/Update: new theory of function updates:
  1347     f(a:=b) == %x. if x=a then b else f x
  1348 may also be iterated as in f(a:=b,c:=d,...);
  1349 
  1350 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1351 
  1352 * HOL/List:
  1353   - new function list_update written xs[i:=v] that updates the i-th
  1354     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1355   - new function `upt' written [i..j(] which generates the list
  1356     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1357     bound write [i..j], which is a shorthand for [i..j+1(].
  1358   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1359 
  1360 * HOL/Arith:
  1361   - removed 'pred' (predecessor) function;
  1362   - generalized some theorems about n-1;
  1363   - many new laws about "div" and "mod";
  1364   - new laws about greatest common divisors (see theory ex/Primes);
  1365 
  1366 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1367 instead of "inverse";
  1368 
  1369 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1370   of the multiset ordering;
  1371 
  1372 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1373   (not included by default);
  1374 
  1375 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1376 
  1377 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1378   programs, i.e. different program variables may have different types.
  1379 
  1380 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1381   [previously, this check worked only if the rewrite rule was unconditional]
  1382   Now rew can involve either definitions or equalities (either == or =).
  1383 
  1384 
  1385 *** ZF ***
  1386 
  1387 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1388   only the theorems proved on ZF.ML;
  1389 
  1390 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1391   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1392   disjointness reasoning but breaking a few old proofs.
  1393 
  1394 * ZF/Update: new theory of function updates
  1395     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1396   may also be iterated as in f(a:=b,c:=d,...);
  1397 
  1398 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1399 
  1400 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1401   [previously, this check worked only if the rewrite rule was unconditional]
  1402   Now rew can involve either definitions or equalities (either == or =).
  1403 
  1404 * case_tac provided for compatibility with HOL
  1405     (like the old excluded_middle_tac, but with subgoals swapped)
  1406 
  1407 
  1408 *** Internal programming interfaces ***
  1409 
  1410 * Pure: several new basic modules made available for general use, see
  1411 also src/Pure/README;
  1412 
  1413 * improved the theory data mechanism to support encapsulation (data
  1414 kind name replaced by private Object.kind, acting as authorization
  1415 key); new type-safe user interface via functor TheoryDataFun; generic
  1416 print_data function becomes basically useless;
  1417 
  1418 * removed global_names compatibility flag -- all theory declarations
  1419 are qualified by default;
  1420 
  1421 * module Pure/Syntax now offers quote / antiquote translation
  1422 functions (useful for Hoare logic etc. with implicit dependencies);
  1423 see HOL/ex/Antiquote for an example use;
  1424 
  1425 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1426 cterm -> thm;
  1427 
  1428 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1429 subgoal;
  1430 
  1431 * Display.print_goals function moved to Locale.print_goals;
  1432 
  1433 * standard print function for goals supports current_goals_markers
  1434 variable for marking begin of proof, end of proof, start of goal; the
  1435 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1436 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1437 for example;
  1438 
  1439 
  1440 
  1441 New in Isabelle98 (January 1998)
  1442 --------------------------------
  1443 
  1444 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1445 
  1446 * changed lexical syntax of terms / types: dots made part of long
  1447 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1448 
  1449 * simpset (and claset) reference variable replaced by functions
  1450 simpset / simpset_ref;
  1451 
  1452 * no longer supports theory aliases (via merge) and non-trivial
  1453 implicit merge of thms' signatures;
  1454 
  1455 * most internal names of constants changed due to qualified names;
  1456 
  1457 * changed Pure/Sequence interface (see Pure/seq.ML);
  1458 
  1459 
  1460 *** General Changes ***
  1461 
  1462 * hierachically structured name spaces (for consts, types, axms, thms
  1463 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1464 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1465 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1466 long_names for fully qualified output names; NOTE: ML programs
  1467 (special tactics, packages etc.) referring to internal names may have
  1468 to be adapted to cope with fully qualified names; in case of severe
  1469 backward campatibility problems try setting 'global_names' at compile
  1470 time to have enrything declared within a flat name space; one may also
  1471 fine tune name declarations in theories via the 'global' and 'local'
  1472 section;
  1473 
  1474 * reimplemented the implicit simpset and claset using the new anytype
  1475 data filed in signatures; references simpset:simpset ref etc. are
  1476 replaced by functions simpset:unit->simpset and
  1477 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1478 to patch your ML files accordingly;
  1479 
  1480 * HTML output now includes theory graph data for display with Java
  1481 applet or isatool browser; data generated automatically via isatool
  1482 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1483 
  1484 * defs may now be conditional; improved rewrite_goals_tac to handle
  1485 conditional equations;
  1486 
  1487 * defs now admits additional type arguments, using TYPE('a) syntax;
  1488 
  1489 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1490 creates a new theory node; implicit merge of thms' signatures is
  1491 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1492 transfer:theory->thm->thm in (rare) cases;
  1493 
  1494 * improved handling of draft signatures / theories; draft thms (and
  1495 ctyps, cterms) are automatically promoted to real ones;
  1496 
  1497 * slightly changed interfaces for oracles: admit many per theory, named
  1498 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  1499 
  1500 * print_goals: optional output of const types (set show_consts and
  1501 show_types);
  1502 
  1503 * improved output of warnings (###) and errors (***);
  1504 
  1505 * subgoal_tac displays a warning if the new subgoal has type variables;
  1506 
  1507 * removed old README and Makefiles;
  1508 
  1509 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  1510 
  1511 * removed obsolete init_pps and init_database;
  1512 
  1513 * deleted the obsolete tactical STATE, which was declared by
  1514     fun STATE tacfun st = tacfun st st;
  1515 
  1516 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  1517 (which abbreviates $HOME);
  1518 
  1519 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  1520 use isatool fixseq to adapt your ML programs (this works for fully
  1521 qualified references to the Sequence structure only!);
  1522 
  1523 * use_thy no longer requires writable current directory; it always
  1524 reloads .ML *and* .thy file, if either one is out of date;
  1525 
  1526 
  1527 *** Classical Reasoner ***
  1528 
  1529 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  1530 tactics that use classical reasoning to simplify a subgoal without
  1531 splitting it into several subgoals;
  1532 
  1533 * Safe_tac: like safe_tac but uses the default claset;
  1534 
  1535 
  1536 *** Simplifier ***
  1537 
  1538 * added simplification meta rules:
  1539     (asm_)(full_)simplify: simpset -> thm -> thm;
  1540 
  1541 * simplifier.ML no longer part of Pure -- has to be loaded by object
  1542 logics (again);
  1543 
  1544 * added prems argument to simplification procedures;
  1545 
  1546 * HOL, FOL, ZF: added infix function `addsplits':
  1547   instead of `<simpset> setloop (split_tac <thms>)'
  1548   you can simply write `<simpset> addsplits <thms>'
  1549 
  1550 
  1551 *** Syntax ***
  1552 
  1553 * TYPE('a) syntax for type reflection terms;
  1554 
  1555 * no longer handles consts with name "" -- declare as 'syntax' instead;
  1556 
  1557 * pretty printer: changed order of mixfix annotation preference (again!);
  1558 
  1559 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  1560 
  1561 
  1562 *** HOL ***
  1563 
  1564 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1565   with `addloop' of the simplifier to faciliate case splitting in premises.
  1566 
  1567 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  1568 
  1569 * HOL/Auth: new protocol proofs including some for the Internet
  1570   protocol TLS;
  1571 
  1572 * HOL/Map: new theory of `maps' a la VDM;
  1573 
  1574 * HOL/simplifier: simplification procedures nat_cancel_sums for
  1575 cancelling out common nat summands from =, <, <= (in)equalities, or
  1576 differences; simplification procedures nat_cancel_factor for
  1577 cancelling common factor from =, <, <= (in)equalities over natural
  1578 sums; nat_cancel contains both kinds of procedures, it is installed by
  1579 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  1580 
  1581 * HOL/simplifier: terms of the form
  1582   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  1583   are rewritten to
  1584   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  1585   and those of the form
  1586   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  1587   are rewritten to
  1588   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  1589 
  1590 * HOL/datatype
  1591   Each datatype `t' now comes with a theorem `split_t_case' of the form
  1592 
  1593   P(t_case f1 ... fn x) =
  1594      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  1595         ...
  1596        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  1597      )
  1598 
  1599   and a theorem `split_t_case_asm' of the form
  1600 
  1601   P(t_case f1 ... fn x) =
  1602     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  1603         ...
  1604        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  1605      )
  1606   which can be added to a simpset via `addsplits'. The existing theorems
  1607   expand_list_case and expand_option_case have been renamed to
  1608   split_list_case and split_option_case.
  1609 
  1610 * HOL/Arithmetic:
  1611   - `pred n' is automatically converted to `n-1'.
  1612     Users are strongly encouraged not to use `pred' any longer,
  1613     because it will disappear altogether at some point.
  1614   - Users are strongly encouraged to write "0 < n" rather than
  1615     "n ~= 0". Theorems and proof tools have been modified towards this
  1616     `standard'.
  1617 
  1618 * HOL/Lists:
  1619   the function "set_of_list" has been renamed "set" (and its theorems too);
  1620   the function "nth" now takes its arguments in the reverse order and
  1621   has acquired the infix notation "!" as in "xs!n".
  1622 
  1623 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  1624 
  1625 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  1626   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  1627 
  1628 * HOL/record: extensible records with schematic structural subtyping
  1629 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  1630 still lacks various theorems and concrete record syntax;
  1631 
  1632 
  1633 *** HOLCF ***
  1634 
  1635 * removed "axioms" and "generated by" sections;
  1636 
  1637 * replaced "ops" section by extended "consts" section, which is capable of
  1638   handling the continuous function space "->" directly;
  1639 
  1640 * domain package:
  1641   . proves theorems immediately and stores them in the theory,
  1642   . creates hierachical name space,
  1643   . now uses normal mixfix annotations (instead of cinfix...),
  1644   . minor changes to some names and values (for consistency),
  1645   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  1646   . separator between mutual domain defs: changed "," to "and",
  1647   . improved handling of sort constraints;  now they have to
  1648     appear on the left-hand side of the equations only;
  1649 
  1650 * fixed LAM <x,y,zs>.b syntax;
  1651 
  1652 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  1653 adm (%x. P (t x)), where P is chainfinite and t continuous;
  1654 
  1655 
  1656 *** FOL and ZF ***
  1657 
  1658 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1659   with `addloop' of the simplifier to faciliate case splitting in premises.
  1660 
  1661 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  1662 in HOL, they strip ALL and --> from proved theorems;
  1663 
  1664 
  1665 
  1666 New in Isabelle94-8 (May 1997)
  1667 ------------------------------
  1668 
  1669 *** General Changes ***
  1670 
  1671 * new utilities to build / run / maintain Isabelle etc. (in parts
  1672 still somewhat experimental); old Makefiles etc. still functional;
  1673 
  1674 * new 'Isabelle System Manual';
  1675 
  1676 * INSTALL text, together with ./configure and ./build scripts;
  1677 
  1678 * reimplemented type inference for greater efficiency, better error
  1679 messages and clean internal interface;
  1680 
  1681 * prlim command for dealing with lots of subgoals (an easier way of
  1682 setting goals_limit);
  1683 
  1684 
  1685 *** Syntax ***
  1686 
  1687 * supports alternative (named) syntax tables (parser and pretty
  1688 printer); internal interface is provided by add_modesyntax(_i);
  1689 
  1690 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  1691 be used in conjunction with the Isabelle symbol font; uses the
  1692 "symbols" syntax table;
  1693 
  1694 * added token_translation interface (may translate name tokens in
  1695 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  1696 the current print_mode); IMPORTANT: user print translation functions
  1697 are responsible for marking newly introduced bounds
  1698 (Syntax.mark_boundT);
  1699 
  1700 * token translations for modes "xterm" and "xterm_color" that display
  1701 names in bold, underline etc. or colors (which requires a color
  1702 version of xterm);
  1703 
  1704 * infixes may now be declared with names independent of their syntax;
  1705 
  1706 * added typed_print_translation (like print_translation, but may
  1707 access type of constant);
  1708 
  1709 
  1710 *** Classical Reasoner ***
  1711 
  1712 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  1713 some limitations.  Blast_tac...
  1714   + ignores addss, addbefore, addafter; this restriction is intrinsic
  1715   + ignores elimination rules that don't have the correct format
  1716         (the conclusion MUST be a formula variable)
  1717   + ignores types, which can make HOL proofs fail
  1718   + rules must not require higher-order unification, e.g. apply_type in ZF
  1719     [message "Function Var's argument not a bound variable" relates to this]
  1720   + its proof strategy is more general but can actually be slower
  1721 
  1722 * substitution with equality assumptions no longer permutes other
  1723 assumptions;
  1724 
  1725 * minor changes in semantics of addafter (now called addaltern); renamed
  1726 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  1727 (and access functions for it);
  1728 
  1729 * improved combination of classical reasoner and simplifier:
  1730   + functions for handling clasimpsets
  1731   + improvement of addss: now the simplifier is called _after_ the
  1732     safe steps.
  1733   + safe variant of addss called addSss: uses safe simplifications
  1734     _during_ the safe steps. It is more complete as it allows multiple
  1735     instantiations of unknowns (e.g. with slow_tac).
  1736 
  1737 *** Simplifier ***
  1738 
  1739 * added interface for simplification procedures (functions that
  1740 produce *proven* rewrite rules on the fly, depending on current
  1741 redex);
  1742 
  1743 * ordering on terms as parameter (used for ordered rewriting);
  1744 
  1745 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  1746 
  1747 * the solver is now split into a safe and an unsafe part.
  1748 This should be invisible for the normal user, except that the
  1749 functions setsolver and addsolver have been renamed to setSolver and
  1750 addSolver; added safe_asm_full_simp_tac;
  1751 
  1752 
  1753 *** HOL ***
  1754 
  1755 * a generic induction tactic `induct_tac' which works for all datatypes and
  1756 also for type `nat';
  1757 
  1758 * a generic case distinction tactic `exhaust_tac' which works for all
  1759 datatypes and also for type `nat';
  1760 
  1761 * each datatype comes with a function `size';
  1762 
  1763 * patterns in case expressions allow tuple patterns as arguments to
  1764 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  1765 
  1766 * primrec now also works with type nat;
  1767 
  1768 * recdef: a new declaration form, allows general recursive functions to be
  1769 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  1770 
  1771 * the constant for negation has been renamed from "not" to "Not" to
  1772 harmonize with FOL, ZF, LK, etc.;
  1773 
  1774 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  1775 infinite lists;
  1776 
  1777 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  1778 
  1779 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  1780 problems in commutative rings, using axiomatic type classes for + and *;
  1781 
  1782 * more examples in HOL/MiniML and HOL/Auth;
  1783 
  1784 * more default rewrite rules for quantifiers, union/intersection;
  1785 
  1786 * a new constant `arbitrary == @x.False';
  1787 
  1788 * HOLCF/IOA replaces old HOL/IOA;
  1789 
  1790 * HOLCF changes: derived all rules and arities
  1791   + axiomatic type classes instead of classes
  1792   + typedef instead of faking type definitions
  1793   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  1794   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  1795   + eliminated the types void, one, tr
  1796   + use unit lift and bool lift (with translations) instead of one and tr
  1797   + eliminated blift from Lift3.thy (use Def instead of blift)
  1798   all eliminated rules are derived as theorems --> no visible changes ;
  1799 
  1800 
  1801 *** ZF ***
  1802 
  1803 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  1804 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  1805 as ZF_cs addSIs [equalityI];
  1806 
  1807 
  1808 
  1809 New in Isabelle94-7 (November 96)
  1810 ---------------------------------
  1811 
  1812 * allowing negative levels (as offsets) in prlev and choplev;
  1813 
  1814 * super-linear speedup for large simplifications;
  1815 
  1816 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  1817 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  1818 FAIL); can suppress it using the command Delsimps (ex_simps @
  1819 all_simps); De Morgan laws are also now included, by default;
  1820 
  1821 * improved printing of ==>  :  ~:
  1822 
  1823 * new object-logic "Sequents" adds linear logic, while replacing LK
  1824 and Modal (thanks to Sara Kalvala);
  1825 
  1826 * HOL/Auth: correctness proofs for authentication protocols;
  1827 
  1828 * HOL: new auto_tac combines rewriting and classical reasoning (many
  1829 examples on HOL/Auth);
  1830 
  1831 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  1832 the rewriter and classical reasoner simultaneously;
  1833 
  1834 * function uresult no longer returns theorems in "standard" format;
  1835 regain previous version by: val uresult = standard o uresult;
  1836 
  1837 
  1838 
  1839 New in Isabelle94-6
  1840 -------------------
  1841 
  1842 * oracles -- these establish an interface between Isabelle and trusted
  1843 external reasoners, which may deliver results as theorems;
  1844 
  1845 * proof objects (in particular record all uses of oracles);
  1846 
  1847 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  1848 
  1849 * "constdefs" section in theory files;
  1850 
  1851 * "primrec" section (HOL) no longer requires names;
  1852 
  1853 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  1854 
  1855 
  1856 
  1857 New in Isabelle94-5
  1858 -------------------
  1859 
  1860 * reduced space requirements;
  1861 
  1862 * automatic HTML generation from theories;
  1863 
  1864 * theory files no longer require "..." (quotes) around most types;
  1865 
  1866 * new examples, including two proofs of the Church-Rosser theorem;
  1867 
  1868 * non-curried (1994) version of HOL is no longer distributed;
  1869 
  1870 
  1871 
  1872 New in Isabelle94-4
  1873 -------------------
  1874 
  1875 * greatly reduced space requirements;
  1876 
  1877 * theory files (.thy) no longer require \...\ escapes at line breaks;
  1878 
  1879 * searchable theorem database (see the section "Retrieving theorems" on
  1880 page 8 of the Reference Manual);
  1881 
  1882 * new examples, including Grabczewski's monumental case study of the
  1883 Axiom of Choice;
  1884 
  1885 * The previous version of HOL renamed to Old_HOL;
  1886 
  1887 * The new version of HOL (previously called CHOL) uses a curried syntax
  1888 for functions.  Application looks like f a b instead of f(a,b);
  1889 
  1890 * Mutually recursive inductive definitions finally work in HOL;
  1891 
  1892 * In ZF, pattern-matching on tuples is now available in all abstractions and
  1893 translates to the operator "split";
  1894 
  1895 
  1896 
  1897 New in Isabelle94-3
  1898 -------------------
  1899 
  1900 * new infix operator, addss, allowing the classical reasoner to
  1901 perform simplification at each step of its search.  Example:
  1902         fast_tac (cs addss ss)
  1903 
  1904 * a new logic, CHOL, the same as HOL, but with a curried syntax
  1905 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  1906 look like (a,b) instead of <a,b>;
  1907 
  1908 * PLEASE NOTE: CHOL will eventually replace HOL!
  1909 
  1910 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  1911 It translates to the operator "split".  A new theory of integers is available;
  1912 
  1913 * In ZF, integer numerals now denote two's-complement binary integers.
  1914 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  1915 
  1916 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  1917 of the Axiom of Choice;
  1918 
  1919 
  1920 
  1921 New in Isabelle94-2
  1922 -------------------
  1923 
  1924 * Significantly faster resolution;
  1925 
  1926 * the different sections in a .thy file can now be mixed and repeated
  1927 freely;
  1928 
  1929 * Database of theorems for FOL, HOL and ZF.  New
  1930 commands including qed, qed_goal and bind_thm store theorems in the database.
  1931 
  1932 * Simple database queries: return a named theorem (get_thm) or all theorems of
  1933 a given theory (thms_of), or find out what theory a theorem was proved in
  1934 (theory_of_thm);
  1935 
  1936 * Bugs fixed in the inductive definition and datatype packages;
  1937 
  1938 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  1939 and HOL_dup_cs obsolete;
  1940 
  1941 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  1942 have been removed;
  1943 
  1944 * Simpler definition of function space in ZF;
  1945 
  1946 * new results about cardinal and ordinal arithmetic in ZF;
  1947 
  1948 * 'subtype' facility in HOL for introducing new types as subsets of existing
  1949 types;
  1950 
  1951 
  1952 $Id$